分子蒸馏精制棕榈油甘油二酯工艺研究

利用分子蒸馏小试装置研究了分离较高纯度棕榈油甘油二酯的生产工艺。利用Novozym 435脂肪酶在无溶剂体系下甘油解棕榈油,制备甘油二酯含量大于50%的酰基甘油混合物,采用两级分子蒸馏进行精制,并研究了二级分子蒸馏温度、刮膜转速、进料速率对甘油二酯纯度的影响。结果表明:在二级分子蒸馏真空度0.1 Pa、蒸馏温度230℃、刮膜转速300 r/min、进料速率4 m L/min的条件下,得到了纯度达到80%左右、得率达到50%左右的棕榈油甘油二酯产品。     

分子蒸馏技术纯化甘油二酯工艺优化及产品分析

为得到高纯度的甘油二酯产品,利用分子蒸馏技术对酶催化合成的甘油二酯进行脱酸和纯化。在分别考察进料速率、蒸发面温度和刮板转速对分子蒸馏效果影响的基础上,正交试验得到最佳工艺条件及结果为一级分子蒸馏进料速率2 mL/min、蒸发面温度170 ℃、刮板转速300 r/min,此时纯度达72.51%;经二级分子蒸馏后产品纯度92.31%、酸值0.97 mg KOH/g。与大豆色拉油相比,蒸馏后甘油二酯的硬脂肪酸含量升高,稳定性好,碘值、皂化值和过氧化值降低。     

分子蒸馏技术富集沙棘果油中棕榈油酸的研究

采用分子蒸馏技术对沙棘果油中的棕榈油酸进行了富集研究,通过单因素和正交实验,得到最佳工艺条件:刮膜器转速120 r/min,进料速度1.0~1.2 m L/min,蒸馏压力0.1 Pa,第一次蒸馏温度为100℃,第二次蒸馏温度为90℃。得到的轻组分得率为19.3%,其中棕榈油酸质量分数为51.9%。     

分子蒸馏法纯化宽叶缬草挥发油中的乙酸龙脑酯

采用分子蒸馏法对缬草挥发油进一步纯化。在单因素实验的基础上,通过响应面法优化分子蒸馏技术纯化缬草挥发油所需温度、进料速度、刮膜转速的最佳工艺参数,采用弹性石英毛细管柱TR-5,在检测器温度为250℃,气化温度为250℃,分流比为50∶1条件下进行GC法测定,并用内标法定量。考察蒸发温度,刮膜速率,进料速度等对缬草挥发油的主要成分乙酸龙脑酯的含量的影响。结果表明:最佳工艺条件为:进料速度为82 m L/h,蒸馏温度68℃,刮膜转速188 r/min,乙酸龙脑酯的质量分数为77.46%。结论:通过分子蒸馏法可得到比传统的水蒸气蒸馏法所提挥发油的有效成分质量分数要高,在挥发油提纯工业化生产方面有很好的应用前景。     

鱼油中棕榈油酸的分离纯化

采用尿素包合-分子蒸馏复合法对乙酯化鱼油的棕榈油酸进行富集。尿素包合的条件为反应温度75℃,m鱼油∶m尿素∶m乙醇=1∶2∶4。通过单因素试验研究刮膜转速、进料速度和蒸馏温度对棕榈油酸含量的影响。在单因素试验基础上,应用响应面分析优化得到分子蒸馏富集棕榈油酸的最优条件:设备真空度3.0×10-3 kPa,刮膜转速160 r/min,进料速度0.5 mL/min,蒸馏温度65℃。在此条件下最终产品中棕榈油酸含量从原料油中的8.41%提升到32.29%,回收率为60.5%。     

响应面法优化分子蒸馏提纯C_(22)-环脂三酸二丁一甲酯工艺

应用响应面法优化分子蒸馏提纯C_(22)-环脂三酸二丁一甲酯工艺。在单因素实验基础上,采用Box-Behnken设计方法考察了蒸馏温度、蒸馏压力、刮膜转速及进料速率对C_(22)-环脂三酸二丁一甲酯纯度和收率的影响。结果表明,分子蒸馏提纯C_(22)-环脂三酸二丁一甲酯的最佳工艺条件为:蒸馏温度125℃,蒸馏压力47 Pa,刮膜转速206 r/min,进料速率1.12 g/min。在最佳工艺条件下,C_(22)-环脂三酸二丁一甲酯的纯度为90.42%,收率为84.94%。     

尿素包合法联合分子蒸馏技术提纯乙酯化鱼油中EPA及DHA的工艺研究

联合尿素包合法及分子蒸馏技术对乙酯化鱼油中的EPA和DHA进行提纯.尿素包合试验中考察了脲酯比、醇脲比、结晶温度及结晶时间等因素对产品纯度及回收率的影响,选择试验条件为脲酯比2:1、醇脲比4:1、结晶温度0℃及结晶时间1h进行尿素包合试验,得到EPA及DHA总纯度为63.5％的产品,回收率为48.5％.分子蒸馏试验中考察了蒸馏温度、预热温度、内冷温度、刮膜器转速及进料速率等因素对试验结果的影响,选择在蒸馏温度90℃、预热温度40℃、内冷温度15℃、刮膜器转速360 r/min、进料速率2 mL/min及真空度0.1 Pa的条件下对乙酯化鱼油进行二次提纯,产品中EPA及DHA总纯度为78.9％,回收率为49％.     

分子蒸馏精制槟榔油加工技术研究

在单因素实验基础上,以进料温度、进料速率、蒸馏温度、转速为考察对象,以槟榔油重相馏出物为指标,采用L9(34)正交表对槟榔油分子蒸馏纯化工艺进行优化;结果得到最佳工艺为:进料温度45℃、进料速率1.8 ml/min、蒸馏温度130℃、转速200 r/min;验证结果表明,该最佳工艺稳定、可靠。     

分子蒸馏精炼MCT工艺的研究

研究了二级分子蒸馏法精炼MCT的工艺方法.通过进料量、压力、温度的控制得到了纯度为97%的MCT.其最佳的操作条件为:一级分子蒸馏进料量1.6 L/h,温度105～110℃,压力10 Pa;二级分子蒸馏进料量1.2 L/h,温度200～210℃,压力1 Pa.     

分子蒸馏技术分离纯化橘皮油中柠檬烯

探讨用分子蒸馏技术从橘皮油中提取高品质柠檬烯的最优工艺条件.采用二级蒸馏分离,以柠檬烯的得率和纯度总和为考察指标,在单因素试验的基础上,采用L9(34)正交试验来确定蒸馏压力、蒸馏温度、进料速度、刮膜转速4个因素的最佳组合工艺条件.二级分子蒸馏选择蒸馏压力为40 Pa,进料速度1.5 mL/min,蒸馏温度为80℃,刮膜转速为280 r/min的条件,可获得纯度高达99%,得率达到86.54%的柠檬烯.该工艺操作稳定可靠、便于控制、环保和易于实现工业化.     

Textural Properties of Cold-set Gels Induced from Heat-denatured Whey Protein Isolates

A 9% whey protein (WP) isolate solution at pH 7.0 was heat-denatured at 80°C for 30 min. Size-exclusion HPLC showed that native WP formed soluble aggregates after heat-treatment. Additions of CaCl2 (10–40 mM), NaCl (50–400 mM) or glucono-delta-lactone (GDL, 0.4–2.0%, w/v) or hydrolysis by a protease from Bacillus licheniformis caused gelation of the denatured solution at 45°C. Textural parameters, hardness, adhesiveness, and cohesiveness of the gels so formed changed markedly with concentration of added salts or pH by added GDL. Maximum gel hardness occurred at 200 mM NaCl or pH 4.7. Increasing CaCl2 concentration continuously increased gel hardness. Generally, GDL-induced gels were harder than salt-induced gels, and much harder than the protease-induced gel.     

Occurrence of bisphenol-F-diglycidyl ether (BFDGE) in fish canned in oil

The levels of bisphenol-F-diglycidyl ether (BFDGE) were quantified as part of a European survey on the migration of residues of epoxy resins into oil from canned fish. The contents of BFDGE in cans, lids and fish collected from all 15 Member States of the European Union and Switzerland were analysed in 382 samples. Cans and lids were separately extracted with acetonitrile. The extraction from fish was carried out with hexane followed by re-extraction with acetonitrile. The analysis was performed by reverse phase HPL C with fluorescence detection. BFDGE could be detected in 12% of the fish, 24% of the cans and 18% of the lids. Only 3% of the fish contained BFDGE in concentrations considerably above 1mg/kg. In addition to the presented data, a comparison was made with the levels of BADGE (bisphenol-A-diglycidyl ether)analysed in the same products in the context of a previous study.     

Contribution of European research to risk analysis

The European Commission's, Quality of Life Research Programme, Key Action 1—Health, Food & Nutrition is mission-oriented and aims, amongst other things, at providing a healthy, safe and high-quality food supply leading to reinforced consumer confidence in the safety of European food. Its objectives also include the enhancing of the competitiveness of the European food supply. Key Action 1 is currently supporting a number of different types of European collaborative projects in the area of risk analysis. The objectives of these projects range from the development and validation of prevention strategies including the reduction of consumers risks; development and validation of new modelling approaches; harmonization of risk assessment principles, methodologies, and terminology; standardization of methods and systems used for the safety evaluation of transgenic food; providing of tools for the evaluation of human viral contamination of shellfish and quality control; new methodologies for assessing the potential of unintended effects of genetically modified (genetically modified) foods; development of a risk assessment model for Cryptosporidium parvum related to the food and water industries; to the development of a communication platform for genetically modified organism, producers, retailers, regulatory authorities and consumer groups to improve safety assessment procedures, risk management strategies and risk communication; development and validation of new methods for safety testing of transgenic food; evaluation of the safety and efficacy of iron supplementation in pregnant women; evaluation of the potential cancer-preventing activity of pro- and pre-biotic ('synbiotic') combinations in human volunteers. An overview of these projects is presented here.     

低温带皮菜籽粕微粉的不同粒级部分的功能特性

为研究低温带皮菜籽粕微粉的不同粒级部分的功能特性,以经低温脱脂的带皮菜籽粕为原料,经微粉碎后筛分成212~425μm、150~212μm和106~150μm的3个不同粒级的微粉样品,检测这些样品的吸水性、吸油性、乳化性和乳化稳定性、蛋白质体外消化率。结果表明:1 3个不同粒级的微粉样品之间的粗纤维含量存在显著差异,表明三者的结构组成成分有一定差异。23个微粉样品的乳化活性和乳化稳定性随粒度级别的减小而显著增加(P0.01)。33个微粉样品的蛋白质体外消化率随粒度级别的减小而显著增加(P0.01)。4不同粒级带皮菜籽粕微粉样品的吸水性与吸油性受其结构组成物质不同和粒度的双重影响,与粒度的相关性不明显。     

Microbiology of food taints

Fresh and processed foods are often spoilt by the presence of undesirable flavours and odours caused by microbial action. The aim of this paper is to review the current knowledge of microbiologically induced taints that occur in a wide range of foodstuffs, including meats, poultry, fish, crustaceans, milk, dairy products, fruits, vegetables, cereals and cereal products. Examples have been chosen where the compounds responsible for the taint have been identified and sufficient data obtained to demonstrate the involvement of microorganisms. However, in some cases the full identity of the causative organism may not have been elucidated. The types of microorganisms covered by this review include bacteria, fungi, yeasts, actinomycetes and cyanobacteria. Although cyanobacteria do not in general infect foods, their presence in aqueous systems and water supplies can lead to off-flavours in aquatic organisms and processed foodstuffs. Several examples of each of these processes are discussed. Wherever possible, the likely biosynthetic pathway used by the microorganism to produce the offending compound in a foodstuff is indicated.     

Analysis for organic residues from aids to polymerization used to make plastics intended for food contact

Polymers intended for food contact use have been analysed for organic residues which could be attributed to a range of substances employed as polymerization aids (e.g. initiators and catalysts). A wide range of polymers was extracted with solvents and the extracts analysed by gas chromatography-mass spectrometry (GC-MS). The overwhelming majority of substances identified were not derived from aids to polymerization but were oligomers, additives and adventitious contaminants. However, a small number of substances were identified as initiator residues. These included tetramethylsuccinonitrile (TMSN) which was observed in two polymers and it derived from recombination of two azobisisobutyronitrile (AIBN) initiator radicals. Methyl benzoate, benzoic acid, biphenyl and phenyl benzoate were detected in one poly(methyl methacrylate) sample and in two polyvinylchlorides and they are thought to be derived from benzoyl peroxide initiator. TMSN was subsequently targeted for analysis of poly-(methyl methacrylate) plastics using proton nuclear magnetic resonance spectrometry (¹     

Tests of potential functional barriers for laminated multilayer food packages. Part II: Medium molecular weight permeants

Experiments were performed to characterize the kinetics of the permeation of different medium molecular weight model permeants: bisphenol A, warfarin and anthracene, from liquid paraffin, through a surrogate potential functional barrier (25 microns-thick orientated polypropylene--OPP) into the food simulants olive oil and 3% (w/v) acetic acid. The characterization of permeation kinetics generally observed the permeation models previously reported to explain the experimental permeation results obtained for a low molecular weight group of model permeants. In general, the model permeants exhibited behaviour consistent with their relative molecular weights with respect to (a) the time taken to attain steady-state permeation into the food simulant in which they were more soluble, (b) their subsequent steady-state permeation rates, and (c) their partition between liquid paraffin and the OPP membrane.     

The development of reference materials for paralytic shellfish poisoning toxins in lyophilized mussel. I: Interlaboratory studies of methods of analysis

This paper describes the first part of a project undertaken to develop mussel reference materials for Paralytic Shellfish Poisoning (PSP) toxins. Two interlaboratory studies were undertaken to investigate the performance of the analytical methodology for several PSP toxins, in particular saxitoxin (STX) and decarbamoyl-saxitoxin (dc-STX) in lyophilized mussels, and to set criteria for the acceptance of results to be applied during the second part of the project: the certification exercise. In the first study, 18 laboratories were asked to measure STX and dc-STX in rehydrated lyophilized mussel material and to identify as many other PSP toxins as possible with a method of their choice. In the second interlaboratory study, 15 laboratories were additionally asked to determine quantitatively STX and dc-STX in rehydrated lyophilized mussel and in a saxitoxin-enriched mussel material. The first study revealed that three out of four postcolumn derivatization methods and one pre-column derivatization method sufficed in principle to determine STX and dc-STX. Most participants (13 of 18) obtained acceptable calibration curves and recoveries. Saxitoxin was hardly detected in the rehydrated lyophilized mussels and results obtained for dc-STX yielded a CV of 58% at a mass fraction of 1.86 mg/kg. Most participants (14 out of 18) identified gonyautoxin-5 (GTX-5) in a hydrolysed extract provided. The first study led to provisional criteria for linearity, recovery and separation. The second study revealed that 6 out of 15 laboratories were able to meet these criteria. Results obtained for dc-STX yielded a CV of 19% at a mass fraction of 3.49mg/kg. Results obtained for STX in the saxitoxin-enriched material yielded a CV of 19% at a mass fraction of 0.34mg/kg. Saxitoxin could not be detected in the PSP-positive material. Hydrolysis was useful to confirm the identity of GTX5 and provided indicative information about C1 and C2 toxins in the PSP-positive material. The methods used in the second interlaboratory study showed sufficiently consistent analysis results to undertake a certification exercise to assign certified values for STX and dc-STX in lyophilized mussel.     

The Ministry of Environmental Protection Issued "Feasible Technology Guidelines for Pollution Prevention and Control in Wood Pulping Process of the Paper Industry (Trial)" and Two Other Guiding Technical Documents

On December 27t＂, 2013, the Ministry of Environmenta Protection announced that, in order to implement ＂The Environmental Protection Law of the People＇ s Republic of China＂, improve the working system in environmenta protection technologies, and promote technologica advancement in pollution prevention, the Ministry of Environmental Protection sponsored the formulation of three guiding technical documents including ＂Feasible Technology Guidelines for Pollution Prevention and Contro n Wood Pulping Process of the Paper Industry （Trial）＂     

1~(st) Intelli-Tissue~ EcoEc Tissue Machine Supplied by PMP Group Successfully Put into Operation in China

正On April 29th,2014,Intelli-Tissue EcoEc tissue machine supplied by PMP Group successfully put into operation at Hebei Xuesong Paper Co.,Ltd.,this is the first such kind of paper machine of PMP Group in China.